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Diffstat (limited to 'Documentation/admin-guide/mm/damon/start.rst')
| -rw-r--r-- | Documentation/admin-guide/mm/damon/start.rst | 71 |
1 files changed, 61 insertions, 10 deletions
diff --git a/Documentation/admin-guide/mm/damon/start.rst b/Documentation/admin-guide/mm/damon/start.rst index 7aa0071ff1c3..ede14b679d02 100644 --- a/Documentation/admin-guide/mm/damon/start.rst +++ b/Documentation/admin-guide/mm/damon/start.rst @@ -7,7 +7,7 @@ Getting Started This document briefly describes how you can use DAMON by demonstrating its default user space tool. Please note that this document describes only a part of its features for brevity. Please refer to the usage `doc -<https://github.com/awslabs/damo/blob/next/USAGE.md>`_ of the tool for more +<https://github.com/damonitor/damo/blob/next/USAGE.md>`_ of the tool for more details. @@ -26,7 +26,7 @@ User Space Tool For the demonstration, we will use the default user space tool for DAMON, called DAMON Operator (DAMO). It is available at -https://github.com/awslabs/damo. The examples below assume that ``damo`` is on +https://github.com/damonitor/damo. The examples below assume that ``damo`` is on your ``$PATH``. It's not mandatory, though. Because DAMO is using the sysfs interface (refer to :doc:`usage` for the @@ -34,18 +34,69 @@ detail) of DAMON, you should ensure :doc:`sysfs </filesystems/sysfs>` is mounted. +Snapshot Data Access Patterns +============================= + +The commands below show the memory access pattern of a program at the moment of +the execution. :: + + $ git clone https://github.com/sjp38/masim; cd masim; make + $ sudo damo start "./masim ./configs/stairs.cfg --quiet" + $ sudo damo report access + heatmap: 641111111000000000000000000000000000000000000000000000[...]33333333333333335557984444[...]7 + # min/max temperatures: -1,840,000,000, 370,010,000, column size: 3.925 MiB + 0 addr 86.182 TiB size 8.000 KiB access 0 % age 14.900 s + 1 addr 86.182 TiB size 8.000 KiB access 60 % age 0 ns + 2 addr 86.182 TiB size 3.422 MiB access 0 % age 4.100 s + 3 addr 86.182 TiB size 2.004 MiB access 95 % age 2.200 s + 4 addr 86.182 TiB size 29.688 MiB access 0 % age 14.100 s + 5 addr 86.182 TiB size 29.516 MiB access 0 % age 16.700 s + 6 addr 86.182 TiB size 29.633 MiB access 0 % age 17.900 s + 7 addr 86.182 TiB size 117.652 MiB access 0 % age 18.400 s + 8 addr 126.990 TiB size 62.332 MiB access 0 % age 9.500 s + 9 addr 126.990 TiB size 13.980 MiB access 0 % age 5.200 s + 10 addr 126.990 TiB size 9.539 MiB access 100 % age 3.700 s + 11 addr 126.990 TiB size 16.098 MiB access 0 % age 6.400 s + 12 addr 127.987 TiB size 132.000 KiB access 0 % age 2.900 s + total size: 314.008 MiB + $ sudo damo stop + +The first command of the above example downloads and builds an artificial +memory access generator program called ``masim``. The second command asks DAMO +to start the program via the given command and make DAMON monitors the newly +started process. The third command retrieves the current snapshot of the +monitored access pattern of the process from DAMON and shows the pattern in a +human readable format. + +The first line of the output shows the relative access temperature (hotness) of +the regions in a single row hetmap format. Each column on the heatmap +represents regions of same size on the monitored virtual address space. The +position of the colun on the row and the number on the column represents the +relative location and access temperature of the region. ``[...]`` means +unmapped huge regions on the virtual address spaces. The second line shows +additional information for better understanding the heatmap. + +Each line of the output from the third line shows which virtual address range +(``addr XX size XX``) of the process is how frequently (``access XX %``) +accessed for how long time (``age XX``). For example, the evelenth region of +~9.5 MiB size is being most frequently accessed for last 3.7 seconds. Finally, +the fourth command stops DAMON. + +Note that DAMON can monitor not only virtual address spaces but multiple types +of address spaces including the physical address space. + + Recording Data Access Patterns ============================== The commands below record the memory access patterns of a program and save the monitoring results to a file. :: - $ git clone https://github.com/sjp38/masim - $ cd masim; make; ./masim ./configs/zigzag.cfg & + $ ./masim ./configs/zigzag.cfg & $ sudo damo record -o damon.data $(pidof masim) -The first two lines of the commands download an artificial memory access -generator program and run it in the background. The generator will repeatedly +The line of the commands run the artificial memory access +generator program again. The generator will repeatedly access two 100 MiB sized memory regions one by one. You can substitute this with your real workload. The last line asks ``damo`` to record the access pattern in the ``damon.data`` file. @@ -57,7 +108,7 @@ Visualizing Recorded Patterns You can visualize the pattern in a heatmap, showing which memory region (x-axis) got accessed when (y-axis) and how frequently (number).:: - $ sudo damo report heats --heatmap stdout + $ sudo damo report heatmap 22222222222222222222222222222222222222211111111111111111111111111111111111111100 44444444444444444444444444444444444444434444444444444444444444444444444444443200 44444444444444444444444444444444444444433444444444444444444444444444444444444200 @@ -122,6 +173,6 @@ Data Access Pattern Aware Memory Management Below command makes every memory region of size >=4K that has not accessed for >=60 seconds in your workload to be swapped out. :: - $ sudo damo schemes --damos_access_rate 0 0 --damos_sz_region 4K max \ - --damos_age 60s max --damos_action pageout \ - <pid of your workload> + $ sudo damo start --damos_access_rate 0 0 --damos_sz_region 4K max \ + --damos_age 60s max --damos_action pageout \ + <pid of your workload> |